Self-contained pre-manufactured air unit for installation on a roof of a building

ABSTRACT

A self-contained pre-manufactured air unit for installation on a roof of a building and method of operation thereof has a relief passage for connection to a building to receive relief air from the building when air pressure within the building exceeds a pressure of ambient air. The relief passage is independent of an air circulation system and is located to exhaust relief air over the condenser coil to ambient air through at least one condenser fan, thereby decreasing a temperature of a refrigerant in the condenser coil.

SUMMARY

This invention relates to a self-contained pre-manufactured air unit for installation on the roof of a building. A condenser coil is located in a first portion of a housing of the air unit that has access to ambient air and is independent of a second portion of the housing. Air from the building is directed through an independent relief passage over the condenser coil to decrease the temperature of refrigerant within the condenser coil before being exhausted to ambient air.

SUMMARY OF PARTICULAR EMBODIMENTS

It will be appreciated by those skilled in the art that other variations of the embodiments described below may also be practiced without departing from the scope of the invention. Further note, these embodiments, and other embodiments of the present invention will become more fully apparent from a review of the description and claims which follow.

It is an object of the present invention to provide a self-contained pre-manufactured air unit for installation on a roof of a building where the independent relief passage and the condenser coil are positioned and configured such that all of the relief air flows over the condenser coil in the first portion of the housing. In addition, the condenser coil is open to an ambient airstream. The relief air is reduced into the ambient airstream. When the relief air temperature is less than the ambient air temperature, the temperature of the air flowing over the condenser coil is reduced below ambient temperatures, improving the efficiency of the refrigeration circuit.

When ambient air temperatures are less than room temperature, partial cooling of the building using outdoor air is possible. Operation of the refrigeration circuit is therefore significantly less when ambient air temperatures are less than the room temperature compared to when ambient air temperatures are greater than the room temperature. The relief air temperature is therefore less than ambient air temperatures for the majority of the time periods that the refrigeration circuit is in operation. Considerable energy savings are therefore possible by using the relief air to lower the temperature of the air flowing over the condenser coil.

As ambient air flows into the return airstream and subsequently into the building, if it is to be used for space cooling purposes its temperature must first be reduced so that it is below room temperature. This requires an energy flow from the air to the refrigerant using a cooling coil. To create this flow of energy, the refrigerant must be cooler than the air. Operation of a compressor(s) and the consumption of electricity is required to cool the refrigerant to the required level. By using the relief air to help cool the refrigerant in the condenser coil, the energy which was consumed to cool the ambient air is partially reclaimed. As the relief air flows out of the building and over the condenser coil, energy is transferred from the refrigerant back to the air. Since the refrigerant in the condenser coil is warmer than the relief air, this transfer occurs without the use of electricity or other energy sources. This results in an energy savings and improved refrigeration circuit efficiency

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood that the drawings are only for the purpose of illustration and as an aid to understanding and are not intended as a definition of the limits of the invention. The embodiments herein will be understood from the following description with reference to the drawings, in which:

FIG. 1 is a perspective side view of a self-contained pre-manufactured air unit in accordance with the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components outlined in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. In particular, all terms used herein are used in accordance with their ordinary meanings unless the context or definition clearly indicates otherwise. Also, unless indicated otherwise except within the claims the use of “or” includes “and” and vice-versa. Non-limiting terms are not to be construed as limiting unless expressly stated or the context clearly indicates otherwise (for example, “including”, “having”, “characterized by” and “comprising” typically indicate “including without limitation”). Singular forms included in the claims such as “a”, “an” and “the” include the plural reference unless expressly stated or the context clearly indicates otherwise. Further, the stated features and/or configurations or embodiments thereof the suggested intent may be applied as seen fit to certain operating conditions or environments by one experienced in the field of art.

In FIG. 1, an air unit 2 has a housing 4 a first passage 6 to supply air to the building, a second passage 8 to receive return air from the building and a blower 10 to circulate air into and out of the building. The housing 4 has a first portion 9 and a second portion 11. The blower, the first passage and the second passage are an air circulation system.

A relief passage 12 is connected to the building (not shown) to receive relief air from the building when air pressure within the building exceeds a pressure of ambient air. A condenser coil 14 is located within the first portion 9 of the housing 4 near the relief passage 12. One or more compressors 16 are preferably located within portion 11. The one or more compressors are connected through refrigeration piping (not shown) to the condenser coil 14. At least one condenser fan 18 is located in the first portion to draw air from the relief passage over the coil 14 to exhaust the air to ambient air. In addition, the at least one condenser fan 18 draws ambient air over the coil 14 from a space around the relief passage 12 (in this case the space is shown triangular, but other shapes will be suitable). A part of the first portion 9 that includes the relief passage 12 is open to ambient air at a front and rear of the housing 4.

Preferably, the second portion 11 of the housing 4 near the second passage 8 has an ambient air inlet 20 located to allow ambient air to enter the housing and mix with the return air to supply some fresh air to the building.

Self-contained pre-manufacturing rooftop heating/cooling units are known to be equipped with a refrigerant type cooling coil. Operating in conjunction with the cooling coil is a refrigeration circuit which includes a compressor(s) and a condenser coil. Heat is transferred from the warm recirculating airstream to the cold refrigerant within the cooling coil. The compressor then compresses the refrigerant, causing its temperature to rise and enabling the refrigerant to release heat to the ambient air through the condenser coil. A fan is known to be used to cause ambient air to flow over the condenser coil and increase the rate of heat removal from the refrigerant. As the temperature of the air flowing over the condenser coil is reduced, the rate at which heat is removed from the refrigerant is increased and the efficiency at which the refrigeration circuit operates is also increased.

Rooftop units which are equipped with refrigerant type cooling coils are intended to cool the air which is supplied to the building, which will subsequently cool the building. The refrigeration circuit is known to operate when the ambient air temperatures are above typical room temperatures.

Rooftop units are known to be equipped with an ambient air intake opening to ventilate and/or cool the building. Ventilation is known to be required during all building occupied periods to maintain acceptable air quality levels and the quantity of ambient air introduced into a building is known to increase above a minimum limit in direct relation to the quantity of building occupants. Ambient air is known to be used to cool the building when the temperature of the ambient air is less than the room temperature. Cooling using outdoor air is known to save considerable energy since the condenser fan and compressor(s) forming part of the refrigeration circuit are not required to operate when the building is cooled using ambient air. To prevent over-pressurization of the building, all ambient air which is introduced into the building must be removed in an equal quantity.

For rooftop units which are equipped with cooling coils, the ambient air which is introduced into the building for ventilation purposes is known to be cooled by the cooling coil which is integral to the rooftop unit before it is introduced into the building. In this case, energy is used to reduce the temperature of ambient ventilation air to room temperature. After the ventilation air has been utilized within the building, previous rooftop units discharge the relief air to the exterior of the building without reclaiming any of the energy that was used to cool this air. When the temperature of the relief air is less than that of the ambient air, there is energy which can be reclaimed.

The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, functions, operations, or steps, any of these embodiments may include any modification, combination or permutation of any of the components, elements, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. All such modifications, combinations and permutations are believed to be within the sphere and scope of the invention as defined by the claims appended hereto. 

We claim:
 1. A self-contained pre-manufactured air unit for installation on a roof of a building, for circulating air through the building, the unit comprising a housing having a blower therein, a condenser coil containing refrigerant and a compressor, a first passage to supply air to the building, a second passage to receive return air from the building, the blower connected to circulate air into and out of the building through the first passage and the second passage respectively, the blower and the first passage and second passage comprising an air circulation system that is located in a second portion of the housing, a relief passage for connection to the building to receive relief air from the building when air pressure within the building exceeds a pressure of ambient air, the relief passage being independent of the air circulation system and located to exhaust relief air over the condenser coil to ambient air through at least one condenser fan, thereby decreasing a temperature of the refrigerant, the relief passage and at least one condenser coil located in a first portion of the housing.
 2. The air unit as claimed in claim 1 wherein the first portion of the housing is ambient air accessible to an area of the relief passage to allow ambient air to mix with relief air and to flow over the condenser coil.
 3. The air unit as claimed in claim 2 wherein the first portion of the housing is open to ambient air near the relief passage.
 4. The air unit as claimed in claim 1 wherein the condenser coil is one selected from the group of a heating coil, a cooling coil and a heating/cooling coil.
 5. The air unit as claimed in claim 1 wherein a compressor for the coil is located in the second portion of the housing.
 6. A method of operating a self-contained pre-manufactured air unit for installation on a roof of a building, the unit comprising a housing having a blower therein a condenser coil containing refrigerant and a compressor, a first passage to supply air to the building, a second passage to receive return air from the building, the blower connected to circulate air into and out of the building through the first passage and the second passage respectively, the blower, the first passage and second passage comprising an air circulation system, a method comprising locating a relief passage for connection to the building to receive relief air from the building when air pressure was in the building exceeds a pressure of ambient air, locating the relief passage to be independent of the air circulation system and to exhaust relief air over the condenser coil to ambient air through at least one condenser fan to decrease a temperature of the refrigerant locating the coil in a first portion of the housing and locating the first passage, the second passage and the blower in a second portion of the housing. 